The present invention relates generally to control mechanisms for water treatment systems, and in particular to a control mechanism for controlling two water treatment tanks.
Water treatment devices of the ion exchange type, often referred to as water softeners, typically include a tank having a resin bed through which hard water passes to exchange its hard ions of calcium and magnesium for the soft sodium ions of the resin bed. Regeneration of the resin bed is periodically required to remove the accumulation of hard ions and to replenish the supply of soft ions. Regeneration is usually accomplished by flushing a brine solution from a brine tank through the resin bed. The brine tank typically includes a reservoir and a supply of salt. A supply of water is provided to the reservoir wherein the water reacts with the salt to produce the source of brine for regeneration of the resin bed. Water treatment systems may include two tanks each of which includes a resin bed. While one tank is on-line supplying treated water, the other tank may be regenerated and kept off-line in a stand-by mode. Resin tanks typically include an elongate cylinder in which the ion exchange resin is contained, an inlet formed at the top of the resin tank and a riser pipe which extends downwardly from an outlet at the top of the tank to the bottom of the tank within the resin bed. The present invention provides a control mechanism for selectively taking first and second tanks on-line and off-line and for controlling the regeneration process of each tank.